1. Field of the Invention
The present invention relates to a UFBGA (ultra fine pitch ball grid array) package equipped with an interface assembly, and particularly to an improved UFBGA package equipped with an interface assembly having external electrode protrusions, an anisotropic conductive film, and a photosoluble film.
2. Description of the Conventional Art
A conventional BGA (ball grid arrays) package is well known to those who skilled in the art. In particular, the BGA package is well disclosed in the magazine NEKKEI Electronics of May, 1994 at pages 42 thorough 45. The BGA package, as shown in FIG. 1, includes a semiconductor chip 3 disposed at a central portion of a substrate 1 and bonded by an epoxy adhesive 2. In addition, pads (not shows) of the semiconductor chip 3 and a conductive pattern (not shown) formed on the substrate are electrically connected with a wire 4. In addition, solder balls 6 are bonded to an external terminal 5 formed on the lower surface of the substrate 1.
Meanwhile, after connecting the wire 4 and molding the BGA package with an epoxy molding compound (EMC), a plurality of spaced-apart solder balls 6 are aligned at the lower surface of the substrate 1 and is processes in a reflow method, so that the solder balls 6 are bonded.
However, the reliability of the BGA package made through the above-mentioned processes is completely dependent on the soldering process. When inferior product occurs during an electric test, in a state that the temperature is increased, since the entire BGA package should be changed, it is difficult to effectively maintain the system.
Moreover, in the BGA package, when solder balls are not well bonded to the printed circuit board, the impedance value is sharply increased in an external electric test. In this case, even part of the solder balls is inferior it is necessary to melt the entire solder balls and to substitute with a new BGA package after a cleaning process, so that when error package is found, the entire process should be changed.